Improvement in steam-boilers



UNITED STATES WILLIAM OLDMAN, OF BUFFALO, N-EVV YORK.

IMPROVEMENT IN STEAM-BOILERS.

Specification forming part of Letters Patent No. 24,326, dated June 7,1859.

To all whom it may concern:

Be it known that I, WILLIAM OLDMAN, of Buifalo, in the county, of Erieand State of New York, have invented a new and useful Improvement inSteam-Boilers; and I do hereby declare that the following is a full,clear, and exact description of the same, reference being had to theaccompanying drawings, forming part of this specification, in which-Figure l is a vertical section; Fig. 2, a horizontal section, and Fig. 3an outline diagram to illustrate a portion.

The nature of my invention consists in giving a dishing or partiallyspherical form to the tube-sheets, which receive and sustain each end ofthe tubes, the'hollow or concave side of one tube-sheet being presentedtoward the swelled or convex side of the other, in order to allow moreexpansion and contraction to the tubes than is allowed by the use ofplane tube-sheets.

1t also consists in a peculiar arrangement of the tubes in reference toeach other and to one of the dishing or spherical tube-sheets, wherebythe elasticity of the metal is made more available.

It also consists in providing in the withindescribed relation to anannular water-space on the exterior a liberal water-space extending downthe center of the chamber above and communicating with the large centralwater-space between the tubes, whereby an active current of water isinduced to wash the lower tube-sheet.

To enable others skilled in the art to make Y and use my invention, Iwill proceed to describe its construction and operation.-

My grate A is circular. An annular waterspace or water-leg, B,completely encircles the ire, with the exception of an ordinary door onone side. (N ot represented.) Across the top of the inside re-box orfurnace extends a crown-sheet or tube-sheet, O, which is not plane, asare all ordinary tube-sheets, but is slightly arched, or, rather, domed,the sheet being convex on its upper face and concave on its lower face,as represented. This sheet C is thickly perforated with holes, in whichare secured the ends of the tubes D, through which the products ofcombustion escape from the furnace. These tubesD are slightly inclinedfrom the perpendicular, diverging as they ascend. I arrange them inthree or more sections, as shown in Fig. 2, and dispose the tubes in anyone section parallel to the other tubes in the same section. The upperextremities of these tubes are secured in a sheet, E, which -is notplane, but, like C, is dishing orspherical, the convex side beingpresented upward. The sheet E, like the sheet C, is of a circular form.The sheet E is larger than the sheet C. By the divergence of the tubes Da larger sheet is required to secure them at their upper than at theirlower extremities, and not only is the area of the curved portiongreater, but for obvious reasons the radius of the curvature or dish ofE is greater than that of O. The sheet E is of so large area that itextends somewhat beyond the limits required to receive the ends of D;but the annular portion E exterior to the tubes D, is not dished. It isplane like the ordinary tubesheets, as represented in Fig. 1. The diIergence of the upper ends of the tubesDleaves a considerable space inthe center, which, like the smaller interstices between the tubes, isallowed to be filled with water.

Above the annular space in which the upper ends of D are secured is aspacious box or combustion-chamber, F, in an annular form, asrepresented. In this chamber the unburned gases rising from fresh fuelhave a renewed opportunity to mingle with the free oxygen and flame andbe burned. This combustion-chamber F is ofsuch diameter that it extendsover the plane annular portion E of the sheet E. The water-spacestanding in the center of the combustion-chamber (denoted F) may beeither cylindrical or conical. I have represented it as conical, thelargerv diameter uppermost. The combustion-chamber F may be of anyheight consistent with the height of the entire boiler, care being takento have its top well stayed to the top of the boiler and to be sure thatthere is always sufcient water on it to avoid danger of its overheating.I

rIhe exterior or shell of the boiler is of larger diameter at the middleand top than .descend from the combustion-chamber F. -Escaping from thelower ends of H they im- A pinge upon a horizontal plate, I, whichsurrounds the shell of the boiler at a lower level,

as represented, and are then free to ascend in an annular space, N,provided between the shell of the boiler and a suitable jacket, J, andto escape through the stack K in theordinary manner. This ,jacket may,if preferred, be double and contain water between its parts, in order toheat such water preparatory to its being forced into the boiler; but I'have represented it as a simple jacket of thin metal.V The top oftheboiler and of the jacket may be of any form consistent with strength,

either dome-like or spherical, conical," as represented, or of any otherform, according to the height allowable and as the desire to obtain drysteam may dictate.

The steam is taken from the, boiler 'at or near its top, in the usualmanner, by a pipe,

(not represented,) and there are suitable man-holes and hand-holds (notrepresented) through the boiler and through the jacket to allow access'for repairs.

The hot gases rising from the re ascend through the tubes D, impartingheat to the water surrounding and between them. Ascending from Dslightly cooled, lthey mingle and complete their combustion in thechamber F, and thence descend through the tubes H to the annularsmoke-box M, from which they rise in a current completely surroundingthe boiler, imparting heat to the contents at every step, and escapecomparatively cool into the stack K.

The active circulation of the water in the boiler is represented byeither the red or black arrows. `As the combustion-chamber F extendsvery nearly across the whole shell, it is evident that the steamgenerated between the tubes and about the furnace must rise to thesurface of the Water through the central waterspace, F', and the narrowannular space F between F and the shell, or through one of these alone.As the steam in rising tends to drag up large quantities of water, whichmust be replaced by water descending at some other point, an activecurrent is invariably established, the water either liowing up throughthe central water-space, F', as shown by the red arrows, and down thenarrow annular space F, or down through the central space, F and upthrough F, as shown by the black arrows. The direction of the current inthis respect depends on the proportions of the boiler andthe'temperature of the gases rising within the jacket on the outsideofthe shell;

but whether it be upward or downward through F it must necessarily flowin the reverse direction through F,and thus the water flows radiallyeither outwardly or inwardly through the spaces betweenvthe tubes D, andbeing by its momentum projected downward it thus continually washes theconvex'surface vof the tube-sheet C, preventing any accumulation ofsediment, and consequently preventing the oxidation or burning of thishighlyheated and delicate portion of the boiler. The

onlyquiet water is at the bottom of the water-leg B. There the sedimentconsequently collects and may be removed as often as required by theordinary means, there being no tubes and few or no stays to" diminishthe effect of Scrapers or of waterinjected from hose. f

Fig; 3 is intended to illustrate the eect of any inequalities in thecontractiom and expansion of the tubes and tube-sheets.' F`4llVhen`thetubes expand with heat and demand increased room between the'tube-sheets, the irregular transverse strain on each sheet if planebecomes so great at some points as sometimes to destroy them. In myboiler both the sheet C and the sheet E are capable of yieldingsomewhat, but the lower sheet much the least. The upper sheet, E, iscapable of yielding very much, owing to the fact that the tubes arearranged in sections, and that that portion ofthe sheet between thesections is free to spring. Fig. 3 is a diagram of a cross-section onthe line T T. The red line shows the curvature assumed by the freeportion of the tube-sheet when the tubes contract, and the blue lineclose beneath it shows the nearly plane form assumed by this portionwhen, by reason of the expansion of the tubes, the tube-sheet E isrequired to rise, and consequently to extend itself. Plane sheetscorrugate irregularly when compressed, and are obviously incapable ofany yielding to ya force of extension; but my dishing or sphericalsheets, with the tubes arrangsd in sections, allow a sufficient amountof yielding to obviate the difficulty. By the curvature or dishing formalready established in the sheet and by the division of the space intoseveral suitable sections, as represented, a compressive force simplyincreases the curvature in a slight and harmless degree very muchexaggerated by the red line in Fig. 3, while a tensile force simplydiminishes the curvature, as represented exaggerated by the blue line inthe same iigure.

I have ascertained by experience that this boiler is more efficient ingenerating steam than any others of similar size not tubular, and ismuch less `troublesome to keep tight (and it is presumed will be muchmore durable) than other forms of tubular boilers.

Having now fully described my invention,

What I- olaim as new therein, and desire to seactive circulation of theWater radially among cure by Letters Patent, is- 1 the tubes with theadvantages above eX- The central Water-space, F', in the oombusplained.

tion-chamber F, arranged in relation to the any nular Water-space F andto the tubes D, or Witnesses:

their respective equivalents, substantially as CHILIoN M. FARRAR,

Within set forth, for the purpose of inducing an W. H. EASTMAN.

WILLIAM OLDMAN.

